The U.S. Food and Drug Administration today approved Vimizim (elosulfase alfa), the first FDA-approved treatment for Mucopolysaccharidosis Type IVA (Morquio A syndrome). Morquio A syndrome is a rare, autosomal recessive lysosomal storage disease caused by a deficiency in N-acetylgalactosamine-6-sulfate sulfatase (GALNS). Vimizim is intended to replace the missing GALNS enzyme involved in an important metabolic pathway. Absence of this enzyme leads to problems with bone development, growth and mobility. There are approximately 800 patients with Morquio A syndrome in the United States.

Vimizim was granted priority review. An FDA priority review provides for an expedited review of drugs for serious diseases or conditions that may offer major advances in treatment. Vimizim is also the first drug to receive the Rare Pediatric Disease Priority Review Voucher – a provision that aims to encourage development of new drugs and biologics for the prevention and treatment of rare pediatric diseases.

“This approval and rare pediatric disease priority review voucher underscores the agency’s commitment to making treatments available to patients with rare diseases,” said Andrew E. Mulberg, M.D., deputy director, Division of Gastroenterology and Inborn Errors Products in the FDA’s Center for Drug Evaluation and Research (CDER). “Prior to today’s approval, patients with this rare disease have had no approved drug treatment options.”

The safety and effectiveness of Vimizim were established in a clinical trial involving 176 participants with Morquio A syndrome, ranging in age from 5 to 57 years. Participants treated with Vimizim showed greater improvement in a 6-minute walk test than participants treated with placebo. On average, patients treated with Vimizim in the trial walked 22.5 meters farther in 6 minutes compared to the patients who received placebo.

The most common side effects in patients treated with Vimizim during clinical trials included fever, vomiting, headache, nausea, abdominal pain, chills and fatigue. The safety and effectiveness of Vimizim have not been established in pediatric patients less than 5 years of age. Vimizim is being approved with a boxed warning to include the risk of anaphylaxis. During clinical trials, life-threatening anaphylactic reactions occurred in some patients during Vimizim infusions.